Venipuncture will be employed to collect 2ml of blood from each subject into an EDTA-free vacutainer tube. Samples will be left for 1 hour at 37˚C to allow clotting before storage at 4˚C overnight. The sample will then be centrifuged at 4000 rpm for 20 minutes at 4˚C. Serum will be removed from the clot by pipetting and stored at -80˚C until miRNA extraction is performed.